Study of intramolecular distribution of hydrogen isotopes in ethanol depending on deuterium content of water and the origin of carbohydrates
Abstract
The paper presents the results of consistently developing studies carried out in 2022-2024 on the distribution of deuterium 2H(D) in intracellular water of grapes and wine products, taking into account the influence of natural, climatic and technogenic factors using high-resolution quantitative nuclear magnetic resonance spectroscopy 2H(D)-qNMR. The aim of the current studies was to investigate the intramolecular distribution of hydrogen isotopes on the example of deuterium 2H(D) during alcoholic fermentation carried out under controlled conditions in model systems, the main components of which were water with different content of 2H(D), carbohydrates of different botanical origin (D-glucose, D-fructose, sucrose) and L(+)-tartaric acid from grapes. Taking into account the known scientific data on the effect of the botanical type of carbohydrates on the hydrogen isotopes in the methyl group (CH3-), the main emphasis in the study was placed on the evaluation of the deuterium content of the methylene groups (-CH2-) of ethanol molecules depending on the composition of the system components. The artificially deuterated water containing 2H(D) in the amount of 142-143, 175-212 and 212-284 ppm was used for the preparation of 3 series of model systems. The carbohydrate concentration in the model systems was constant at 200 g/L for all sugars – D-glucose (from grapes), D-fructose (from corn) and sucrose (from sugar beets). The concentration of the acidifier L(+)-tartaric acid was 4 g/L. The content of deuterium in water and ethanol, the isotopic composition of carbon 13C/12C in sugars and ethanol by IRMS/SIRA mass spectrometry, the content of ethanol (GC method) and residual sugar (HPLC method) were studied in all model systems at the beginning and end of fermentation. Experimental data were obtained on the effect of the composition of model systems on the intramolecular distribution of deuterium in ethanol formed during fermentation, as well as on changes in the hydrogen isotopy in the water of the studied model systems using high-resolution nuclear magnetic resonance spectroscopy qNMR under the conditions of the developed measurement method. The results of the fundamental study are a consistent development of the approach to solving the applied problem of assessing the presence of technologically unavoidable water in wine, which in turn provides the basis for identifying unacceptable dilution of wine (must) by adding water from underground and surface sources.
DOI:
Publication date: September 22, 2025
Issue: 46th World Congress of Vine and Wine
Type: Short communication
Authors
1 Peoples’ Friendship University of Russia named after Patrice Lumumba (RUDN University), 117198 Moscow, ul. Mikluho-Maklaya 8/2, Russian Federation
2 Federal State Budget Scientific Institution All-Russian National Research Institute of Viticulture and Winemaking Magarach of the RAS, 298600 Yalta, ul. Kirova 31, Republic of Crimea, Russian Federation